JP2010043926A - Acceleration sensing unit and acceleration sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acceleration sensing unit and an acceleration sensor having reduced size, and improved accuracy for detecting acceleration. <P>SOLUTION: The acceleration sensing unit includes: a fixed member 6 prevented from being displaced by applying the acceleration; a crystalline element supporting member 5 provided with a movable member 8 supported in the fixed member by a beam 7; and a crystalline stress sensitive element 11 having a stress sensitive section, and fixed ends integrated with both ends of the stress sensitive section. The stress sensing element is an acceleration sensing unit having fixed both ends supported by the fixed member and the movable member. A notch for indicating an orientation of a crystal axis of a crystal or a first alignment index 9 having a marking are asymmetrically disposed in a proper place in the element supporting member. A second alignment index 16 for indicating the orientation of the crystal axis of the crystal is asymmetrically disposed in a proper place in the stress sensitive element. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an acceleration detection unit and an acceleration sensor, and more particularly, to a small acceleration detection unit and an acceleration sensor that use the same material for a stress sensitive element and a support member thereof and improve alignment by using an index portion. Is.

Conventionally, acceleration sensors have been widely used from automobiles, airplanes, and rockets to monitoring abnormal vibrations of various plants. Patent Document 1 discloses a piezoelectric vibration type acceleration sensor. FIG. 9A is a plan view of the acceleration sensor, and FIG. 9B is a QQ sectional view. The acceleration sensor 60 includes a cantilever 62 supported at one end by a package, a stress detection element 72 attached to the cantilever 62, and a package 80 (package body 80a and lid member 80b) for accommodating them. It is equipped with. The cantilever 62 is made of an elastically deformable member such as metal (for example, aluminum, brass, etc.), and has a fixed end 66, a free end 64,
And a beam portion 68. When the acceleration is applied to the fixed end 66, the free end 64 is
It is a part that receives the action of inertial force and plays the role of a weight that causes the beam portion 68 to bend.
The beam portion 68 is an element that connects the fixed end 66 and the free end 64, and the acceleration sensor main body 60a.
When acceleration is applied to the sag, bending occurs.
The acceleration detection direction is the Z-axis direction of FIG. 9, and the beam portion 68 is formed in a flat plate shape, thereby preventing swinging in the Y-axis direction orthogonal to the acceleration detection axis direction.
A groove 70 is formed at the longitudinal center of the beam portion 68. When the beam portion 68 is bent, the upper surface of the fixed end 66 and the upper surface of the free end 64 are inclined in opposite directions. If the groove 70 is formed at the center of the beam portion 68, the beam portion 68 bends at the center, and the fixed end 66 of the cantilever beam 62.
Shear stress is generated at both ends of the stress detecting element fixed to the free end 64 and the free end 64, respectively.

As the stress detection element 72, a double tuning fork type piezoelectric vibrating piece is used. The double tuning fork type piezoelectric vibrating piece 72 is a vibrating piece in which two beam vibrating portions 78 are disposed in parallel between two base portions 74 and 76 formed at both ends.
The principle of operation of the acceleration sensor 60 is that the acceleration sensor 60 shown in FIG.
When an acceleration in the axial direction is applied, an inertial force acts on the free end 64 of the cantilever beam 62, and the beam portion 68 bends with the groove 70 as a base point. When the beam portion 68 is bent, a tensile stress or a compressive stress acts on the double tuning fork vibrating piece 72, and the resonance frequency of the double tuning fork vibrating piece 72 increases or decreases due to this stress. The magnitude of the applied acceleration is detected from this frequency change.
Patent Document 2 discloses a beam structure of an acceleration sensor in which both a cantilever beam and a double tuning fork type piezoelectric vibrating piece are made of a quartz material and temperature characteristics are improved. FIG. 10 shows a beam structure of an acceleration sensor according to Patent Document 2. In FIG. 10, reference numeral 90 denotes a crystal double tuning fork vibration element having two vibration beams 91, and reference numeral 92 denotes a crystal double tuning fork vibration element 90. It is an adhesive part (fixed end).
Reference numeral 100 denotes a beam composed of a quartz substrate having the same cut as the quartz double tuning fork vibrating element 90. Then, a protrusion 110 in which only the thickness of the portion of the beam 100 in contact with the bonding portion 92 of the crystal double tuning fork vibrating element 90 is made thicker than the thickness of the other portions is formed integrally with the beam 100, and the protrusion 11
0 and the bonding portion 92 of the double tuning fork vibrating element 90 are bonded and fixed with an adhesive or the like. Furthermore, a weight 120 is provided at the free end of the beam 100, and one end facing the weight 120 is fixed to the base 130.

When a base 130 of an acceleration sensor configured as shown in FIG. 10 is fixed to an object to be measured and acceleration is applied in the direction of the arrow, the weight 120 deflects the beam 100, and the crystal double tuning fork vibrating element 90 fixed to the beam 100 includes The frequency changes under compressive or tensile stress. That is, the acceleration sensor measures the magnitude of acceleration from the amount of change in frequency. By forming the protrusion 110 on the beam 100, the magnitude of the stress applied to the crystal double tuning fork vibrator 90 is increased as compared with the case where there is no protrusion 110, so that the plate thickness of the beam 100 is not reduced. In addition, it is disclosed that a highly sensitive acceleration sensor can be configured without increasing the mass of the weight 120.
Patent Document 3 discloses a weight body that swings under acceleration, a strain body that supports the weight body and is distorted by the swing, and a piezoelectric element that is attached to the strain body and similarly distorted. substrate,
An acceleration sensor is disclosed that includes a leg that supports the strain generating body, a lead wire for taking out an electric signal from the piezoelectric element substrate, and a protective container made of synthetic resin. The piezoelectric element substrate is provided with a marker cut out at one of the four corners, and serves as an index for assembling the acceleration sensor.
JP 2008-39662 A JP-A-2-248866 JP 2001-337102 A

However, when the shape dimensions of the cantilever and the crystal double tuning fork vibrating element are small, for example, when the length is several millimeters and the thickness is 1 mm or less, the acceleration as described in Patent Documents 1 and 2 is used. When the detection unit is configured, there is a problem that variations in acceleration detection sensitivity and acceleration detection accuracy increase.
Moreover, although the marker of the piezoelectric element board | substrate disclosed in patent document 3 is useful for discrimination | determination of the detection axis of an acceleration detection unit, there existed a problem that it was inadequate for the alignment at the time of assembling an acceleration detection unit.
The present invention has been made to solve the above problems, and it is an object of the present invention to provide a small acceleration detection unit and an acceleration sensor with high acceleration detection accuracy.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 An acceleration detection unit according to the present invention includes a fixed member that is not displaced by application of acceleration, a crystal element support member that includes a movable member that is supported by a beam on the fixed member, and a stress sensitive unit. And a stress-sensitive element made of quartz crystal having a fixed end integrated at each end of the stress-sensitive portion, and the beam detects acceleration when the acceleration is applied to the movable member. The stress-sensitive element is an acceleration detection unit in which both fixed ends are supported by the fixed member and the movable member, respectively, and is configured to be deformable so as to be displaced in the axial direction. A notch that indicates the crystal axis direction of the crystal at an asymmetric position on the support member,
Alternatively, the first index portion for alignment consisting of markings is disposed, and the second index portion for alignment is disposed at the asymmetric position on the stress sensitive element while indicating the crystal axis direction of the crystal. This is an acceleration detection unit.

As described above, when the acceleration detection unit is configured by aligning the crystal axis directions of the element support member and the stress sensitive element and using the first and second index portions for alignment, the vertical position of both is accurately aligned, The acceleration detection accuracy and sensitivity are improved, the variation in the detection accuracy of the manufactured acceleration detection unit is reduced, and the temperature characteristics are improved.

Application Example 2 In addition, the acceleration detection unit can match the outer contours of the element support member and the stress sensitive element, and determine the positional deviation between the two using the first and second index portions as a clue. The acceleration detection unit according to claim 1, wherein the acceleration detection unit is configured.

As described above, when the acceleration detection unit is configured using the outer contours of the element support member and the stress sensitive element and the first and second index portions, the vertical positions of the element support member and the stress sensitive element are determined. It is possible to perform bonding accurately, and there is an effect that variations in acceleration detection accuracy and sensitivity of the acceleration detection unit are extremely reduced.

Application Example 3 In addition, the acceleration detection unit forms markings having different shapes or different colors on the corresponding specific portions of the element support member and the stress sensitive element, and marking on the stress sensitive element side. The acceleration detection unit according to claim 1, wherein the presence or absence of matching between the sensor support member and the marking on the element support member side can be confirmed through the stress sensitive element.

As described above, the marking of the half-etched pattern or vapor deposition pattern is provided at the corresponding position between the element support member and the stress-sensitive element, and if the alignment is confirmed with the light transmitted through the marking, the quality of the acceleration detection unit is judged. Thus, there is an effect that an acceleration detection unit with extremely small variations in acceleration detection accuracy and sensitivity can be obtained.

[Application Example 4] In the acceleration detection unit, the notch portion may be a recess for accommodating a break-off residue formed at each of the element support member and an edge of the stress sensitive element. The acceleration detection unit according to claim 1.

As described above, if the break-off residue is used as a notch portion and used as an index in the crystal axis direction, an acceleration detecting unit having stable temperature characteristics can be obtained.

Application Example 5 In the acceleration detection unit, the stress sensitive element includes two fixed ends,
And a double tuning fork type crystal vibrating element provided with a stress sensitive part composed of a piezoelectric substrate provided with two vibration beams connected between the fixed ends, and an excitation electrode formed on a vibration region of the piezoelectric substrate. The acceleration detection unit according to claim 1.

As described above, when an acceleration detection unit is configured using a double tuning fork type crystal vibrating element as a stress sensitive element, the acceleration detection accuracy and sensitivity of the acceleration detection unit are greatly improved, and temperature characteristics and reproducibility are improved. effective.

Application Example 6 An acceleration sensor according to the present invention is an acceleration sensor including the acceleration detection unit according to claim 1 and a package that accommodates the acceleration detection unit. A part of an electrode pattern formed on the inner bottom portion of the package body, the outer contour line of the acceleration detection unit when the acceleration detection unit is mounted at a normal position of the inner bottom portion of the package body. The acceleration sensor is characterized in that it has a matching shape and is set so that a positional deviation can be determined.

As described above, the acceleration detecting unit in which the element supporting member and the stress sensitive element are accurately bonded to each other at a predetermined position is used, and the acceleration detecting unit is aligned with the electrode pattern formed on the inner bottom portion of the package body to accelerate the acceleration. Constructing the sensor has the effect of improving the acceleration detection accuracy, sensitivity, and temperature characteristics, and reducing the detection accuracy and sensitivity variation of the acceleration sensor.

Application Example 7 The acceleration sensor includes an inner bottom portion of the package body, the element support member,
Different markings of different shapes or different colors are formed at corresponding specific parts of the stress sensitive element, and the marking on the divided package side, the marking on the stress sensitive element side, and the marking on the element support member side The acceleration sensor according to claim 6, wherein the presence or absence of matching can be confirmed through the stress-sensitive element.

As described above, using the speed detection unit in which the element support member and the stress sensitive element are accurately bonded, the marking provided on the inner bottom portion of the package body is aligned with the index portion provided on the speed detection unit, and the alignment is performed. If the presence or absence is confirmed by the transmission of light, it is advantageous that the quality of the acceleration sensor can be easily determined.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an exploded perspective view showing a configuration of an acceleration sensor according to an embodiment of the present invention. The acceleration sensor includes a fixed member 6 that is not displaced by the application of acceleration, and a crystal element support member 5 that includes a movable member 8 connected to the fixed member 6 via a beam 7, a stress sensitive portion 12, A stress sensing element 11 made of crystal having fixed ends 13 and 14 respectively integrated at both ends of the stress sensing part 12, and a package 20 (package main body 20a, lid) containing the element supporting member 5 and the stress sensing element 11 Body 20
b).
The element support member 5 has a structure in which the opposite end edges of the rectangular flat plate-like fixed member 6 and the movable member 8 having the same thickness are connected by beams 7. The upper surfaces of the fixed member 6 and the movable member 8 are respectively Both are on the same plane. The thickness of the beam 7 is thinner than the thickness of the fixed member 6 (or the movable member 8), and is integrally connected to the central portion of the side end surfaces of the fixed member 6 and the movable member 8, and the acceleration is the main surface of the element support member 5. When the beam 7 is applied in a direction orthogonal to the acceleration detection axis direction, the beam 7 is configured to bend so as to displace the movable member 8 in the acceleration detection axis direction.
In the three corners of one surface (upper surface) of the element support member 5, as shown in FIG. 1, for example, a plurality of recesses made of half-etched patterns are arranged in two rows and two columns. 1st index part 9 for this is arrange | positioned, As a result, each 1st index part 9 has asymmetrical positional relationship. The reason why the first indicator portion 9 is arranged asymmetrically is to specify the crystal axis (+ X axis) of the crystal. The first indicator portion 9 may be formed by a hole (including a notch), marking (printing, etc.) or the like.
The element support member 5 is etched by using a photolithographic technique and an etching technique, for example, so that a part of the main plane of the rectangular flat plate-shaped quartz substrate is opposed from both sides. It can be formed by a technique in which one is the fixed member 6 and the other is the movable member 8.

As shown in FIG. 1, the stress sensitive element 11 is made of, for example, a quartz substrate as a piezoelectric substrate having two fixed ends 13 and 14 and two vibration beams 12 a connected between the fixed ends 13 and 14. A double tuning fork type crystal vibrating element including a stress sensitive portion 12 and an excitation electrode (not shown) formed on a vibration region of the quartz substrate is used. However, the stress sensitive element 11 is not limited to the double tuning fork type quartz vibrating element 11, and a stress sensitive part including a quartz substrate having two fixed ends and a vibration region connecting between the fixed ends, A quartz crystal resonator element including an excitation electrode formed on a vibration region of the quartz crystal substrate may be used.
When the terminal electrode 15 is formed on one fixed end 13 of the stress sensitive element 11, a second indicator portion 16 (vapor deposition pattern) is provided, and the crystal axis direction is identified on the other fixed end 14. A marking 17 made of characters or the like is formed. The second indicator portions 16 are arranged at the two corners of the rectangular fixed end 13 so as to correspond to the two first indicator portions 9 on the fixing member 6 side, respectively.
When the element support member 5 and the stress sensitive element 11 have the same outer contour size, the element support member 5 and the stress sensitive element 11 are bonded together using an adhesive to form the acceleration detection unit 3. The outer contour can be accurately matched. At this time, in order to align the + X-axis directions of the element support member 5 and the stress sensitive element 11, the first indicator portion 9 (for example, a half etching pattern) on the element support member 5 and the first index portion 9 on the stress sensitive element 11 are arranged. Two index parts 16 (marking with a vapor deposition pattern) and markings 17 (vapor deposition pattern) are used as clues.
In the present embodiment, the axial direction is confirmed by providing the index portions at the three corners of the element support member 5 and one surface of the stress sensitive element 11, but the element support member 5 and the stress When the outline contour dimensions of the sensitive element 11 coincide with each other, it is possible to confirm the axial direction by providing an index portion at one or two corners. Moreover, you may comprise so that the difference between parameter | index parts can be identified by varying the shape and coloring of each parameter | index part.

In addition, the position where the index portion is formed does not have to be a corner portion of one surface of the element support member 5 and the stress sensitive element 11, but an asymmetric position other than a symmetric position such as a central portion of the long side or the short side, For example, any position may be used as long as it is an asymmetric position from which the central part of the long side or the short side is removed. This is true for other embodiments of the invention as well.
The package that accommodates the acceleration detection unit 3 is composed of two divided package pieces, one of the divided package pieces being a package body 20a and the other divided package piece being a lid 20b. The package body 20a is formed of a laminated body 21 of ceramic sheets, and the shape thereof is a box shape having an open top surface as shown in FIG. A pedestal portion 22 is provided at a corner of the inner bottom portion of the package main body 20 a, and an electrode pattern (pad electrode) 23 is formed on the pedestal portion 22. The pad electrode 23 is electrically connected to an external terminal 24 formed on the bottom surface or side surface of the package body 20a by an internal wiring. A seal ring 25 is fired around the periphery of the opening of the package body 20a, and the seal ring 25 is subjected to nickel plating, gold plating, or the like.

The acceleration sensor is obtained by applying a conductive adhesive to the pad electrode 23 on the pedestal portion 22 of the package body 20a, placing the acceleration detection unit 3 on the conductive adhesive, and curing the conductive adhesive. The metallic lid 20b is hermetically welded to the upper surface of the seal ring 25 by seam welding or the like. At this time, the stress sensitive element 11 is maintained by keeping the inside of the package body 20a in a vacuum.
The Q value can be increased, and the sensitivity of the acceleration sensor can be increased. FIG. 2A is a perspective view of the acceleration sensor 1 with the lid 20b removed, and FIG. 2B is a cross-sectional view taken along Q1-Q1.
The operation of the acceleration sensor will be described with reference to FIG. When an acceleration α in the acceleration detection axis direction (+ Z axis direction) is applied to the acceleration sensor 1, a force acts on the acceleration detection unit 3 in the −Z axis direction due to inertial force. Therefore, the acceleration detection unit 3 including the element support member 5 and the stress sensitive element 11 bends in the −Z-axis direction with the beam 7 as a starting point. Stress sensitive element 1
1 are bonded and fixed to the fixed member 6 and the movable member 8 of the element support member 5, respectively, so that the stress sensitive portion 12 is subjected to an extensional stress and the resonance of the stress sensitive element 11. The frequency increases. Conversely, when acceleration (−α) in the −Z-axis direction is applied to the acceleration detection unit 3, a force in the + Z-axis direction is applied by the inertial force, and the acceleration detection unit starts + Z from the beam 7.
It will bend in the axial direction. As a result, compressive stress acts on the stress sensitive part 12, and the resonance frequency of the stress sensitive element 11 decreases. Since the frequency change of the stress sensitive element 11 is substantially proportional to the stress, and the stress is proportional to the acceleration, the magnitude of the applied acceleration can be obtained from the change of the frequency.

Here, the twin tuning fork type crystal vibrating element will be briefly described. The double tuning fork type quartz vibrating element has good sensitivity to tensile and compressive stress, and when used as a stress sensitive element for altimeters or depth gauges, it has a high decomposing ability, so it has a slight pressure difference to high altitude. You can know the difference and depth difference. Further, the frequency temperature characteristic exhibited by the double tuning fork type crystal resonator element is an upwardly convex quadratic curve, and each parameter is set so that the apex temperature becomes room temperature (25 ° C.).
The resonance frequency f _F when the external force F is applied to the two vibrating beams of the double tuning fork type quartz vibrating element is as follows.
f _F = f ₀ (1- (KL ² F) / (2EI)) ^1/2 (1)
Here, f ₀ is the resonance frequency of the double tuning fork type quartz vibrating element when there is no external force, K is a constant according to the fundamental mode (= 0.0458), L is the length of the vibrating beam, E is the longitudinal elastic constant, I Is the moment of inertia of the cross section. Second moment I are from I = dw ^3/12, the equation (1) can be modified as follows. Here, d is the thickness of the vibration beam, and w is the width.
f _F = f ₀ (1−S _F σ) ^1/2 (2)
However, the stress sensitivity _SF and the stress σ are respectively expressed by the following equations.
S _F = 12 (K / E) (L / w) ² (3)
σ = F / (2A) (4)
Here, A is the sectional area (= w · d) of the vibration beam. From the above, when the force F acting on the double tuning fork vibrator is negative in the compression direction and positive in the extension direction (tensile direction), the relationship between the force F and the resonance frequency f _F is that the force F is a compression force and the resonance frequency. f _F decreases and increases with stretching (tensile) force.
The stress sensitivity S _F is proportional to the square of the vibration beam L / w.
However, the stress-sensitive element 30 is not limited to a double tuning fork type crystal vibrating element, and any element may be used as long as it is a piezoelectric vibrating element whose frequency changes due to extension / compression stress. Also,
The relationship between the stress and the apex temperature has a characteristic that the apex temperature shifts to the low tone side when an extensional stress is applied to the double tuning fork type crystal vibrating element and shifts to the high temperature side when compressive stress is applied.

FIG. 3 shows an element support member 5 for increasing the acceleration detection accuracy and sensitivity of the acceleration detection unit 3.
It is the top view which showed the parameter | index part for alignment which improves the bonding precision with the stress sensitive element 11. FIG. In order to improve the acceleration detection accuracy, sensitivity and temperature characteristics of the acceleration detection unit 3,
While aligning the crystal axes (+ X-axis direction) of the element support member 5 and the stress sensitive element 11,
The outer contours of the element support member 5 and the stress sensitive element 11 are made to coincide with each other, and the element support member 5
It is important to keep the main surfaces of the stress sensitive element 11 parallel to each other.
FIG. 3A shows one corner (an asymmetric position) of the fixing portion 6 of the element support member 5 in order to align the crystal axes (+ X-axis direction) of the element support member 5 and the stress sensitive element 11. Notch k1
A (first index portion) is provided, and a marking 17 (second index portion, for example, a vapor deposition pattern) is formed at an asymmetric position on the fixed end 14 of the stress sensitive element 11. The marking 17 may be formed simultaneously when the excitation electrode and the terminal electrode of the stress sensitive element 11 are formed by the photolithography technique and the etching method.
Further, the outer contours (positions of both end edges in the longitudinal direction, contour lines) of the element support member 5 and the stress sensitive element 11 in FIG. For this reason, the direction of the crystal axis is confirmed by providing the index parts k1 and 17 at the asymmetrical positions (positions avoiding the central part of the long side and the short side) of the element support member 5 and the outline of the stress sensitive element. It becomes possible.

The contours of the element support member 5 and the stress sensitive element 11 shown in FIG. 3B are formed in the same shape (positions and contour lines at both ends in the longitudinal direction). A first index portion 9 is formed asymmetrically in a half etching pattern at both corners of the fixed member 6 of the element support member 5 and one corner of the movable member 8;
The + X axis direction can be easily identified. Further, the second index portion 1 having a square shape formed by a vapor deposition pattern is formed at both corners of the fixed end 13 of the stress sensitive element 11 and one corner of the fixed end 14.
6 is formed asymmetrically so that the + X-axis direction can be easily discriminated. Second indicator part 1
6 may be formed simultaneously when the excitation electrode and the terminal electrode of the stress sensitive element 11 are formed by the photolithography technique and the etching technique. The first indicator portion 9 of the element support member 5 and the second indicator portion 16 of the stress sensitive element 11 are formed at positions where they overlap with each other in the vertical direction when their outer contours are matched.
The first and second indicator portions 9 and 16 may be formed by holes, markings, or the like. By distinguishing the appearance of each index part, identification between index parts may be facilitated.
The contours of the element supporting member 5 and the stress sensitive element 11 shown in FIG. 3C (the positions and contour lines of the longitudinal edges) are formed in the same manner. When a plurality of element support members 5 are formed by etching a quartz wafer, a plurality of element support portions 5 connected to each other are prepared. This connection is a state in which the plurality of element support members 5 are integrated through the connection portion protruding from the upper end of the fixed member 6 and the lower end of the movable member 8 or a part of the side surface. The connecting portion has a structure protruding from the inside of the recesses k2, k3, k4, and becomes a broken portion when the element supporting member 5 is separated. As a result, the residue of the connecting portion that is generated when the quartz wafer is broken up and is divided into individual portions is accommodated in the recesses k2, k3, and k4 without protruding from the prescribed outer peripheral dimensions of the element support member 5. The present embodiment is an example in which the recesses k2, k3, and k4 that contain the residue are used as the first index portion for discriminating the crystal axis (+ X axis). Similarly, when the stress sensitive element 11 is formed by folding from an etched quartz wafer, the broken residues k5 and k6 are used as the second index part 16 for identifying the crystal axis (+ X axis). When the element support member 5 and the stress sensitive element 11 are bonded together to form the acceleration detection unit 3, these index portions are used to match the crystal axis directions.
The element support member 5 is formed by forming a plurality of element support member 5 patterns in a lattice pattern on a quartz wafer by a photolithography technique, and by dividing each element support member 5 pattern by a groove for dividing, Recesses k2, k3, k4 are formed. By breaking along the groove,
The individual element support members 5 are formed, and the recesses k2, k3, and k4 are left as residues in the element member 5 at that time.

FIG. 4 is a plan view of the package body 20a. FIG. 4A shows a part of the outline of the electrode pattern (pad electrode) 23 formed on the pedestal portion 22 of the package body 20a with a notch k1. By configuring the same as the shape of the element support member 5, the element support member 5 can be accurately placed at a predetermined position of the pedestal portion 22 of the package body 20a, and can be bonded and fixed.
4B shows that the distance between two electrode patterns (pad electrodes) 23 formed on the pedestal portion 22 of the package body 20a is the same as the width of the element support member 5, and the pad electrode 2
3, the third indicator portion 27 is formed. The third indicator 27 is formed by screen printing or the like at the same time as the electrode pattern (pad electrode) 23 is formed.

FIGS. 5A, 5B, and 5C show the third, first, and third portions formed on the main surfaces of the package main body 20a, the element support member 5, and the stress sensitive element 11 constituting the acceleration sensor 1, respectively. It is a top view which shows the position and shape of the 2nd parameter | index part 27,9,16. Enlarged views of the third, first, and second indicator portions 27, 9, 16 are shown at the bottom of each. In other words, the indicator portions 27, 9, and 16 formed on the package body 20a, the element support member 5, and the stress sensitive element 11 are a cross shape by marking, four crest shapes by a half-etching pattern, and a lip shape by a vapor deposition pattern. I am doing. The element support member 5 and the stress sensitive element 11 are bonded using an adhesive,
When forming the acceleration detection unit 3, the four patterns of the first indicator portion 9 and the second indicator portion 16 are formed.
The shape of the squares accurately overlaps vertically. Further, the acceleration detection unit 3 is connected to the package body 2.
When mounting on 0a, the cross shape (marking) of the third indicator portion 27 formed on the pedestal portion 22 of the package body 20a is accurately overlapped between the four crests of the first indicator portion. Match the dimensions and position.

6A is a plan view of the acceleration sensor, FIG. 6B is a cross-sectional view taken along Q2-Q2, and FIG.
c) is a cross-sectional view taken along Q3-Q3, FIG. 6D is an enlarged view of the index pattern 18 in which the first and second index portions 9 and 16 are accurately overlapped in the vertical direction, and FIG. , Second and third indicator parts 9
, 16 and 27 are enlarged views of the index pattern 19 in which they are accurately overlapped in the vertical direction.
The stress sensitive element 11 is formed on the first index portion 9 (half etching pattern) of the element supporting member 5.
The acceleration detection unit 3 is configured so that the indicator portions 16 (deposition patterns) of the above are accurately overlapped and the main surface of the element support member 5 and the main surface of the stress sensitive element 11 are kept parallel. Since the stress sensitive element 11 and the element supporting member 5 are both made of quartz and are thin and transmit light well, the index shown in FIG. The pattern 18 is visible. That is, four crests of the first index part 9 (half etching pattern) are arranged without overlapping with the four corners of the square shape of the second index part 16 (deposition pattern) of the stress sensitive element 11. Looks like. The outer contour of the acceleration detection unit 3 is defined as the package body 20.
The electrode pattern (pad electrode) 23a is aligned so as to be sandwiched between the electrode patterns (pad electrodes) 23, and the index pattern 18 of the acceleration detection unit 3 is accurately aligned with the cross-shaped third index portion 27 by marking of the package body 20a, and acceleration detection is performed. The acceleration sensor 1 is configured by bonding and fixing so that the main surface of the unit 3 is parallel to the inner bottom surface of the package body 20a. When the acceleration sensor 1 is viewed from above, an index pattern 19 shown in FIG. Conversely, index pattern 1 as shown in FIG.
If 9 is visible, the acceleration detection unit 3 is accurately positioned at a predetermined position of the package body 20a.
In addition, it is adhered in parallel to the bottom surface of the package body 20a.

Next, the acceleration detection unit 3 in which the element support member 5 and the stress sensitive element 11 are accurately bonded, and the main surface of the element support member 5 and the main surface of the stress sensitive element 11 are maintained in parallel, and the package Adhesion and fixation with the main body 20a will be described.
FIG. 7 shows that the acceleration detection unit 3 is bonded and fixed by the adhesive 30 applied to the pedestal portion 22 of the package body 20a in a direction inclined in the short direction of the acceleration detection unit 3 as shown in the sectional view of FIG. This is the case. In this case, as shown in the index pattern 19 in FIG.
The cross shape (marking) of the third index portion 27 is unevenly distributed on one side (short direction) of the index pattern 18 of the acceleration sensor 3.
8 shows that the acceleration detection unit 3 is bonded to the longitudinal direction of the acceleration detection unit 3 by the adhesive 30 applied to the pedestal portion 22 of the package body 20a, as shown in the sectional view of FIG. This is a fixed case. In this case, the third indicator part cross (marking)
However, it is unevenly distributed in one (longitudinal direction) of the index pattern 18 of the acceleration detection unit 3. in this way,
Since the accuracy and sensitivity of acceleration detection are poor when the index pattern 19 is shifted, it is necessary to remove it as a defective product.
Further, when the element support member 5 and the stress sensitive element 11 are bonded and fixed with an adhesive, if the principal surface of the element support member 5 and the principal surface of the stress sensitive element 11 are inclined by the adhesive, the vapor deposition pattern The four half-etched pattern (indicator part 9) does not accurately enter the frame of the braille shape (indicator part 16) and shifts, so this product is easily removed as a defective product at the stage of the acceleration detection unit 3. can do.

As described above, the acceleration detection unit is obtained by aligning the crystal axis directions of the element supporting member 5 and the stress sensitive element 11 and accurately aligning the vertical positions of both using the first and second index portions for alignment. If this is configured, the acceleration detection accuracy and sensitivity are improved, the variation in the detection accuracy of the manufactured acceleration detection unit is reduced, and the temperature characteristics are also improved.
When an acceleration detection unit is configured using the outer contours of the element support member 5 and the stress sensitive element 11 and the first and second index portions, the upper and lower sides of the element support member 5 and the stress sensitive element 11 are The position can be accurately bonded, and an acceleration detection unit with excellent accuracy can be obtained.
Moreover, if the marking by a half-etching pattern or a vapor deposition pattern is provided at the corresponding position between the element support member 5 and the stress sensitive element 11, and the alignment is confirmed by light transmitted through the marking, the quality of the acceleration detection unit is judged. Thus, an acceleration detection unit with extremely small variations in acceleration detection accuracy and sensitivity can be obtained.
Further, if the break-off residue is used as a notch and used as an index in the crystal axis direction, an acceleration detection unit having a stable temperature characteristic can be obtained.
Further, when an acceleration detection unit is configured using a double tuning fork type crystal vibrating element as the stress sensitive element 11, the acceleration detection accuracy and sensitivity of the acceleration detection unit are greatly improved, and temperature characteristics and reproducibility are improved. There is.
In addition, the acceleration detecting unit 3 in which the element supporting member 5 and the stress sensitive element 11 are accurately bonded at a predetermined position is used, and the acceleration detecting unit is aligned with the electrode pattern formed on the inner bottom portion of the divided package piece. By configuring the acceleration sensor, the acceleration detection accuracy, sensitivity, and temperature characteristics are improved, and the detection accuracy and sensitivity variations of the acceleration sensor are reduced.
In addition, the speed detection unit 3 in which the element support member 5 and the stress sensitive element 11 are accurately bonded to each other is used to mark the speed detection unit 3 on the marking formed on the inner bottom portion of the divided package piece.
If the index patterns provided in the above are matched and the presence / absence of the alignment is confirmed by light transmission, the quality of the acceleration sensor can be easily determined.

The disassembled perspective view of the acceleration sensor which concerns on this invention. (A) is a perspective view of the acceleration sensor which concerns on this invention, (b) is sectional drawing. (A), (b), (c) is a top view of an element support member and a pressure sensitive element. (A), (b) is a top view of a package main body, respectively. (A), (b), (c) is the top view of a package main body, an element support member, and a pressure sensitive element, respectively, and the enlarged view of each parameter | index part. (A), (b), (c) is a plan view of the acceleration sensor, a cross-sectional view in the short direction, a cross-sectional view in the longitudinal direction, (d) is an index pattern diagram in which two index portions are overlapped, and (e) is 3 Index pattern diagram where two index parts overlap. FIG. 5A is a plan view, FIG. 5B is a cross-sectional view, and FIG. 5C is an index pattern diagram of an index portion of an acceleration sensor mounted on a package body with the acceleration detection unit tilted in the lateral direction. FIG. 4A is a plan view, FIG. 2B is a cross-sectional view, and FIG. 3C is an index pattern diagram of an index portion of an acceleration sensor mounted on a package body with the acceleration detection unit inclined in the longitudinal direction. (A) is a top view of conventional acceleration sensor, (b) is sectional drawing. The perspective view of the beam structure of the conventional acceleration sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Acceleration sensor, 3 ... Acceleration detection unit, 5 ... Element support member, 6 ... Fixed member, 7 ...
Beam, 8 ... movable member, 9 ... indicator part, 11 ... pressure sensitive element, 12 ... stress sensitive part, 13, 14 ...
Fixed end, 15 ... terminal electrode, 16 ... indicator part, 17, 27 ... marking, 18, 19 ... indicator pattern, 20 ... package, 20a ... package body, 20b ... lid body, 21 ... laminated body, 22
... base part, 23 ... electrode pattern (pad electrode), 24 ... external terminal, 25 ... seal ring,
30 ... Adhesive, k1, k2, k3, k4, k5, k6 ... Notch

Claims (7)

A fixed member that is not displaced by the application of acceleration, and an element support member made of quartz that includes a movable member supported by a beam on the fixed member, and a stress sensitive portion and both ends of the stress sensitive portion are integrated. A stress-sensitive element made of crystal having a fixed end,
The beam is configured to have a flexibility that can be deformed to displace the movable member in an acceleration detection axis direction when acceleration is applied to the movable member.
The stress sensitive element is an acceleration detection unit in which both fixed ends are supported by the fixed member and the movable member,
A notch portion indicating the crystal axis direction of the crystal or a first index portion for alignment made of marking is disposed at the asymmetric position on the element support member, and the crystal is positioned at the asymmetric position on the stress sensitive element. An acceleration detection unit characterized in that a second indicator portion for alignment is arranged while indicating a crystal axis direction. The outer contours of the element support member and the stress sensitive element are made to coincide with each other, and the positional deviation between the element support member and the stress sensitive element can be determined using the first and second index portions as a clue. The acceleration detection unit according to claim 1. Different shapes or different colored markings are formed at corresponding specific parts of the element support member and the stress sensitive element, and the marking on the stress sensitive element side and the marking on the element support member side are matched. 2. The acceleration detection unit according to claim 1, wherein the presence or absence can be confirmed through the stress sensitive element. The acceleration detection unit according to claim 1, wherein the notch is a recess for accommodating a break-off residue formed on an edge of the element support member and the stress sensitive element, respectively. . The stress sensitive element includes a stress sensitive part including a piezoelectric substrate having two fixed ends and two vibration beams connected between the fixed ends, an excitation electrode formed on a vibration region of the piezoelectric substrate, and The acceleration detecting unit according to claim 1, wherein the acceleration detecting unit is a double tuning fork type crystal vibrating element. An acceleration sensor comprising: the acceleration detection unit according to claim 1; and a package that accommodates the acceleration detection unit.
The package has a package main body and a lid, and the acceleration when the acceleration detection unit is mounted at a normal position on the inner bottom of the package main body is formed on a part of the electrode pattern formed on the inner bottom of the package main body. An acceleration sensor characterized in that it has a shape that matches the outline of the detection unit and is set so as to be able to determine misalignment. The package body side marking and the stress-sensitive marking are formed on the inner bottom portion of the package body, the element support member, and the stress-sensitive element by forming different colored markings or different colored markings, respectively. The acceleration sensor according to claim 6, wherein the presence or absence of matching between the element-side marking and the element-supporting member-side marking can be confirmed through the stress-sensitive element.

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